1. Field of the Invention
The present invention relates to an absorbent product for receiving excrement from a wearer.
2. Description of the Background Art
In an absorbent product such as a disposal diaper, conventionally, an absorbent core which is formed by sandwiching crushed pulp and high absorbent resin powder between tissue papers, nonwoven fabrics or the like has been used for absorbing moisture such as urine. Recently, a thin absorbent core where high absorbent resin powder is bonded on a base sheet such as a nonwoven fabric is used; for example, International Patent Publication No. WO 01/54640 (Document 1) discloses a disposal wearing product having a sheet-like absorbent where a layer of highly water absorbing composite composition which is made of micro-fibrillated cellulose and highly water absorbing resin (highly absorbing resin), is partly bonded on a nonwoven fabric support.
In such a thin absorbent not using the crushed pulp, since the absorption speed of the highly water absorbing resin is lower than that of the crushed pulp, if a wearer urinates greatly or the like, there is a possibility that large amounts of urination concentrates on a portion close to a urination portion of the absorbent, absorption of the urination is delayed and leak of urine from an absorbent product occurs.
In Document 1, a technique for preventing concentration of much moisture over an absorption speed of the sheet-like absorbent on a part of the sheet-like absorbent, where the layer of the highly water absorbing composite composition in the sheet-like absorbent is provided on a lower surface of the nonwoven fabric support (the lower surface being opposed to a top sheet), a bulky and thick temporal water-storage layer made of nonwoven fabric whose weight per unit area is 20 to 100 g/m2 is provided between the top sheet and the nonwoven fabric support in the sheet-like absorbent, and thereby, moisture such as urine penetrates to the sheet-like absorbent while dispersing in a planar direction of the temporal water-storage layer. It is possible to make full use of the ability of absorption of the sheet-like absorbent and to prevent leak of urine or the like.
Japanese Patent Application Laid-Open No. 2006-239127 (Document 2) discloses a technique for using a diffusion sheet for an absorbent as a surface sheet (top sheet) of an absorbent product, the diffusion sheet is formed by laminating a thin fineness layer and a thick fineness layer and integrating them by thermal bonding. The thin fineness layer and the thick fineness layer include thermoplastic composite fibers (e.g., polyolefin composite fibers or polyamide composite fibers), and hydrophilic treatment by hydrophilic oil is preferably performed on the thermoplastic composite fibers included in the both layers. In the diffusion sheet of Document 2, body fluid discharged from a wearer rapidly moves to the thick fineness layer by the thin fineness layer, passes through the thick fineness layer to an absorption layer positioned on a lower surface of the diffusion sheet while moving (i.e., dispersing) along the thermoplastic composite fibers in the thick fineness layer in a horizontal direction. Water-repellent fibers are included in the thick fineness layer as well as the thermoplastic composite fibers, in order to suppress moving back of the body fluid which has reached the absorption layer to the wearer, caused by body pressure or the like.
The disposal wearing product of Document 1 is slimmed down as compared with the absorbent product having the absorbent core using the crushed pulp, however, the temporal water-storage layer is bulky and thick and there is a limitation in slimming down of the disposal wearing product. Since the temporal water-storage layer, which is a separated member from the top sheet and the sheet-like absorbent, is provide between the top sheet and the sheet-like absorbent, the structure of the disposal wearing product is complicated and there is a possibility that the manufacturing cost of the disposal wearing product is increased.
In the diffusion sheet of Document 2, the thermoplastic composite fibers with the hydrophilic treatment is used for dispersing moisture in the thick fineness layer and it is not considered that a certain amount of moisture is temporally retained in the thick fineness layer. Therefore, in a case where large amounts of urine or the like is discharged, even if moisture disperses in the thick fineness layer, it is thought much moisture over an absorption speed of the absorption layer moves from the diffusion sheet to the absorption layer in a diffusion range and there is a possibility that leak from the absorbent product occurs.